Design Development\nof Integrated Methane Pyrolysis\nand Reforming Processes for Low-Carbon Urea Production

As the world’s population\ncontinues to grow, the\ndemand\nfor fertilizers is expected to be large. Natural gas through steam\nmethane reforming (SMR) is a major source of greenhouse gas (GHG)\nemissions during traditional ammonia-urea synthesis. Especially in\ncase of ammonia and urea production rates unbalance, CO<sub>2</sub> emissions will increase. By contrast, methane pyrolysis (MP) offers\na more sustainable alternative. Besides making solid carbon as a saleable\nbyproduct, this method also enables the continuous synthesis of ammonia\nand urea with zero CO<sub>2</sub> emissions. This research explores\nthe technical and financial viability of incorporating MP into a traditional\nSMR-ammonia-urea facility by dividing the NG feed between the SMR\nand MP sections. A simulation model was developed using Aspen Plus\nto analyze the integrated system. Results indicate that the proposed\nmodel achieves an optimal methane conversion rate of 73.2%, while\ntargeting carbon black (CB) as a coproduct in the noncatalytic MP\nprocess. In contrast to the traditional plant, the proposed model\ndemonstrates a reduction in power consumption of approximately 5.8\nMW and reduced total direct CO<sub>2</sub> emission intensity (t-CO<sub>2</sub>/t-urea) up to 47.72%. Under conditions mirroring projected\ntrends in the Middle East, where NG prices stand at 2 USD/MMBTU, with\na CO<sub>2</sub> tax policy of 8 USD/ton-CO<sub>2</sub> and a CB price\nof 1500 USD/ton, the proposed model exhibits approximately 8 million\nUSD/yr more profit than the base model. Sensitivity analysis further\nhighlights that the proposed model consistently achieves a higher\nnet present value (NPV) than the base model under varying product\nprices, confirming its superior economic performance across different\nscenarios.